# CVE-2026-33599: A rogue backend can send a crafted SVCB response to a Discovery of Designated Resolvers request, when requested via…

Source: https://junglewise.ai/threats/cve-2026-33599-a-rogue-backend-can-send-a-crafted-svcb-response-to-a-discovery  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-22  
License: CC BY 4.0 with a link back

CVE-2026-33599 · Severity: low · CVSS 3.1 · Published 2026-04-22

A rogue backend can send a crafted SVCB response to a Discovery of Designated Resolvers request, when requested via either the autoUpgrade (Lua) option to newServer or auto_upgrade (YAML) settings. DDR upgrade is not enabled by default.

Technologies: [Powerdns Dnsdist](https://junglewise.ai/threats/technologies/dnsdist). Vendors: [Powerdns](https://junglewise.ai/threats/vendors/powerdns).

## Quick answers

**Is CVE-2026-33599 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-33599 being exploited in the wild.

**How severe is CVE-2026-33599?** Low severity, with a CVSS score of 3.1, published 22 April 2026.

**Which products and versions are affected?** Powerdns Dnsdist. The advisory does not name versions.

**Is there a fix for CVE-2026-33599?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2026-33599?** Check whether you run Powerdns Dnsdist. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Powerdns Dnsdist

## Related threats

- [PowerDNS DNSdist EDNS options smuggling in EDNS processing](https://junglewise.ai/threats/cve-2026-42004-powerdns-dnsdist-edns-options-smuggling-in-edns-processing)
- [PowerDNS DNSdist denial of service in DNS over HTTP/3](https://junglewise.ai/threats/cve-2026-40211-powerdns-dnsdist-denial-of-service-in-dns-over-http-3)
- [PowerDNS DNSdist out-of-bounds read in SetMacAddrAction](https://junglewise.ai/threats/cve-2026-40210-powerdns-dnsdist-out-of-bounds-read-in-setmacaddraction)
- [PowerDNS DNSdist denial of service via IXFR queries](https://junglewise.ai/threats/cve-2026-40209-powerdns-dnsdist-denial-of-service-via-ixfr-queries)
- [PowerDNS DNSdist denial of service in DoH3 queries](https://junglewise.ai/threats/cve-2026-40208-powerdns-dnsdist-denial-of-service-in-doh3-queries)